To calculate how much liquid remains in a volume-based item, WISK uses a combination of data points:

Product's volume - the size of the item (750ml, 1L, etc)

Product's

*full weight*— weight of the item and its contents when fullProduct's

*tare weight*— weight of the empty item excluding the liquid inside*Liquid's density*— necessary to convert weight into volume (liquor categories in WISK already have this value assigned)*Spout weight (optional)*— to account for the added weight of various spout types

Here is a simplified outline of the calculation process:

Get the weight of the partial item from the Bluetooth scale and subtract any added weight from the spouts (if applied)

Check the item's full weight

Check if the item has an empty weight— if we don't have the empty item weight, we can use the item's volume and the liquid's density to determine this value

Compare the full and empty item weights to the partial weight in (1) to determine the proportion of the item's contents that remain

For more information about how the amount remaining is calculated if there is only a full weight on file, see: